INDUCTION OF BASE DAMAGE IN DNA SOLUTIONS BY ULTRASONIC CAVITATION
INDUCTION OF BASE DAMAGE IN DNA SOLUTIONS BY ULTRASONIC CAVITATION
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DOI：
10.1016/0891-5849(94)00119-5
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发表时间：
1995-02-01
影响因子：
7.4
通讯作者：
MILLER, DL
中科院分区：
文献类型：
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作者：
FUCIARELLI, AF;SISK, EC;MILLER, DL
超声可以通过超声空化的机械（剪切）和声化学（产生自由基）作用破坏大分子。将大分子损伤归因于直接机械应力或涉及自由基或其它声化学物质的间接机制是一个具有挑战性的问题。超声诱导的DNA损伤通过测量嘌呤和嘧啶产物的形成，使用气相色谱-质谱联用仪与选择离子监测进行评估。在10 mmol dm（-3）磷酸盐缓冲盐水（pH 7.4）中制备DNA样品，并用氩气：氧气（3：1）的混合物饱和。在60 rpm旋转管暴露系统中以0.82 mPa空间峰值负压幅度进行连续2.17 MHz超声暴露。过氧化氢产量进行了测量后，每次曝光量化的空化活性和范围高达350 μ mol dm（-3）为1小时的曝光。所鉴定的嘌呤和嘧啶产物是在DNA暴露于羟基自由基生成系统（如电离辐射、次黄嘌呤/黄嘌呤氧化酶或过渡金属离子存在下的过氧化氢）后通常观察到的产物。这些产品的产率直接相关的空化活性测定残留过氧化氢浓度。DNA产物的产率按以下顺序增加：胸腺嘧啶乙二醇类似于胞嘧啶乙二醇>8-oxoAde>FAPyAde类似于5-HMU类似于5，6-diOHCyt>FAPyGua。出乎意料的是，8-氧代鸟嘌呤没有表现出高于背景水平的剂量依赖性增加，并且该观察结果与涉及过氧化氢的羟基自由基的金属离子依赖性形成的过程不一致。此外，产物产率太大而不能由残留的过氧化氢产生。因此，超声空化的作用模式似乎与电离辐射或通过与过渡金属的类芬顿反应形成羟基自由基不同。
Ultrasound can damage macromolecules by the mechanical (shearing) and sonochemical (free radical generating) action of ultrasonic cavitation. Attributing macromolecular damage to either direct mechanical stress or to indirect mechanisms involving free radicals or other sonochemicals is a challenging problem. DNA damage induced by ultrasound was evaluated by measuring the formation of purine and pyrimidine products using combined gas chromatography-mass spectrometry with selected ion monitoring. Samples of DNA were prepared in 10 mmol dm(-3) phosphate buffered saline (pH 7.4) and saturated with a mixture of argon:oxygen (3:1). Continuous 2.17 MHz ultrasound exposures at 0.82 mPa spatial peak negative pressure amplitude were performed in a 60 rpm rotating tube exposure system. Hydrogen peroxide yields were measured after each exposure to quantify the cavitation activity and ranged up to 350 mu mol dm(-3) for 1-h exposures. Purine and pyrimidine products identified were those typically observed following exposure of DNA to hydroxyl radical-generating systems, such as ionizing radiation, hypoxanthine/xanthine oxidase, or hydrogen peroxide in the presence of transition metal ions. The yields of these products were directly correlated with cavitation activity as measured by residual hydrogen peroxide concentrations. The yields of DNA products increased in the following order: thymine glycol similar to cytosine glycol>8-oxoAde>FAPyAde similar to 5-HMU similar to 5,6-diOHCyt>FAPyGua. Unexpectedly, 8-oxoguanine did not exhibit a dose-dependent increase above background levels, and this observation is inconsistent with processes involving metal ion-dependent formation of hydroxyl radicals from hydrogen peroxide. In addition, the product yields were far too large to result from the residual hydrogen peroxide. Thus, ultrasonic cavitation appears to have a mode of action distinct from either ionizing radiation or formation of hydroxyl radicals via Fenton-like reaction with transition metals.